Propping frame for mining galleries



1968 L. E. DELOFFRE 3,395,542

PROPPING FRAME FOR MINING GALLERIES Filed March 2, 1966 United StatesPatent Claims. cl. 61-45) ABSTRACT OF THE DISCLOSURE A propping framefor mine galleries having two uprights slidably interconnected by twoarms of a head piece; the arms themselves are slidably clamped to twobranches of a shoe; the branches are joined such as to form a pointedarch and are offset with respect to one another to permit the arms toassume an overlapping position.

It is known to construct propping frames for mining galleries of ahead-piece and two uprights having a trough shaped cross-section, saidparts being interconnected by clamping members which allow their slidingunder the action of the stresses exerted by the ground in which thegallery extends, while the head-piece is constituted by two arms havinga radius of curvature which is substantially equal to that of theuprights and the two adjacent ends of which, possibly interconnected byan intermediate section, form with each other an angle which issubstantially equal to that formed between the ends of the uprights whencollapsed to the maximum extent.

Such frames are a substantial improvement over the conventional framesthat include two uprights provided with an upper arcuate portion havinga radius of curvature which is generally larger than that of the arcuatehead-piece. Said improvement results in a reduction of the gaps arisingbetween the ends of the head-piece and the uprights. The undesirableeffects of such gaps, such as the permanent deformation of the framecomponents, are well known.

It has been found that the use of a head-piece in the shape of a pointedarch or ogive (full or truncated), as defined hereinabove, allowsreducing the gap by about 90% in the case of pressures exertedsubstantially in the direction of the axis of symmetry of the frame.Now, in practice, the pressures are generally oblique, so that theprecedingly described arrangement, although a substantial improvementover prior frames, leaves room for further improvements with a view tostill better absorb the stresses to which it is subjected.

My invention provides such an improvement and it covers a propping frameformed by at least two components assuming, when assembled, the shape ofa complete or truncated ogive. The head-piece of the frame has twoarcuate arms of substantially equal radius of curvature; the arms aremounted slidingly with respect to each other and are slidably secured toa central shoe in such a manner that they are adapted to assume anoverlapping position.

By virtue of said structure, the frame may, by proper selection of theradii and of the centers of curvature, slide under the action of obliqueand vertical thrusts, or only under the action of oblique thrusts whenthe direction thereof is known in advance.

A prepared embodiment of my invention is illustrated by way of examplesin the accompanying drawings where- FIG. 1 is a schematic sideelevational view showing,

without any clamping members, of a propping frame according to myinvention, wherein the two arms of the head piece are slidingly fittedin an ogive-shaped shoe;

FIG. 2 is an enlarged fragmentary view of the headpiece of the frameshown in FIG. 1 with the arms in a different position;

FIG. 3 is a front elevational view of the shoe shown in FIGS. 1 and 2;

FIG. 4 is a plan view of the shoe shown in FIG. 3;

FIGS. 5 and 6 are sectional views taken along lines VV and VIVI of FIG.3; and

FIG. 5a is a view of the shoe similar to FIG. 5 showing an arm of thehead-piece clamped thereto.

The propping frame illustrated in FIG. 1 includes two trough-shaped,symmetrically arranged uprights P1 and P2 each having a rectilinearlower portion and an arcuate upper terminal portion having substantiallythe same radius of curvature. The upper, arcuate portions of the twouprights P1 and P2 are interconnected by a headpiece formed of a centralshoe S and arcuate arms B1, B2 slidably secured thereto and to theuprights. Shoe S includes two integral, symmetrically arranged arcuatebranches b1 and b2 having substantially the same radius of curvature andbeing joined at an angle to form a unitary member having an elevationaloutline of a pointed arch or ogive. The radius of curvature of arms B1and B2 and of uprights P1 and P2 is substantially identical to that ofbranches b1 and b2. In case of maximum subsidence of the propping frameunder action of external forces, the arcuate upper portions of uprightsP1 and P2 will also form an ogive at an angle substantially the same asthat of branches b1 and b2 of shoe S.

A thrust, oblique or otherwise, exerted by the ground, in which thegallery is formed, on a frame such as that illustrated in FIG. 1,results in a sliding in shoe 5 of at least one of the arms B1, B2 to anextent as much as 0.80 to 1 meter without the appearance of anysubstantial gap between any of the uprights and the head-piece, and isusually followed by a relative sliding motion between the ends of thearms B1 and B2 on the one hand and the corresponding ends of therespective uprights P1 and P2 on the other hand.

The central part of the head-piece is schematically illustrated on alarger scale in FIG. 2 in which it will be remarked that the ends of thearms B1 and B2 engaging the respective branches b1 and b2 of the shoe Sare in an overlapping position into which they may be urged by externalforces acting, e.g. in the direction of arrows F shown in FIG. 1.

The reference characters el and e2 schematically indicate -a clampingmeans such as a strap or a U-bolt mounted on branch b1 and b2 andadapted, when tightened, to frictionally but slidably urge arms B1, B2against the respective branch b1, b2 of shoe S.

Turning now to FIGS. 3-6, there is shown the shoe S in more structuraldetail. The shoe S includes a central section 10 joining the juxtaposedend portions of branches b1 and b2 provided with two parallel troughs orupwardly open channels 8 and 9, respectively. The section of channels 8and 9 is so designed that it preferably conforms to the contour of thearms B1 and B2 (FIG. 5a) disposed therein. Troughs 8 and 9 include, inthe vicinity of their free end, bosses 11 and 13 perforated respectivelyat 12 and 14 to receive the legs of a clamping means el and 62 adaptedto frictionally engage respective arms B1 and B2. As shown in FIG. 5a, aclamping means or U-bolt e2 extends transversally across trough 9 whileits legs are received by openings 14--14 in boss 13. The threaded boltends projecting through openings 14, 14 are provided with nuts 15, 15which are suitably tightened to clamp arm B2 to branch b2 of shoe S. Asimilar assembly (not shown) is provided for branch b1.

A propping frame as described hereinabove may, under the action ofvertical or substantially vertical pressures, subside firstsymmetrically and then, under the action of subsequent oblique thrusts,continue sinking with a simultaneous sliding of the shoe S and of thatarm of the head-piece which is adjacent the point of origin of thepressure. The usual respective sliding displacement between the ends ofthe arms B1 and B2 on the one hand and the ends of the uprights on theother hand, occurs subsequently. By virtue of the parallel, offsetarrangement of troughs 8 and 9, the arms B1 and B2 may assume anoverlapping position as shown in FIG. 2.

Although a single embodiment of the invention has been depicted anddescribed, it will be apparent that this embodiment is illustrative innature and that a number of modifications in the apparatus andvariations in its end use may be effected without departing from thespirit or scope of the invention as defined in the appended claims.

What I claim is:

1. A propping frame for mine galleries of the type including twouprights both having an upper arcuate terminal portion, a head-piecesecured to said terminal portions and adapted to slide with respect tosaid uprights under the action of external forces, said head-piece hastwo arcuate portions joined in a pointed arch, the improvement in saidhead-piece comprising, (A) a centrally positioned shoe having (1) twobranches extending in opposite directions and having juxtaposed endportions joined together to form said shoe, (2) channel means extendingarcuately in each of said branches, said channel means being paralleland ofiset with respect to one another,

i 4 (B) two oppositely extending arcu-ate arms each received in one ofsaid channel means and adapted to slide therein in the length dimensionthereof and assume an overlapping position with respect to one another,and (C) clamping means secured to each branch for urging said arms intofrictional engagement with the respective branches of said shoe.

2. The propping frame as defined in claim 1, wherein said channel meansare upwardly open troughs.

3. The propping frame as defined in claim 2, wherein each of saidclamping means includes a portion extending transversally over each ofsaid troughs.

4. The propping frame as defined in claim 3, wherein said clamping meansare constituted by U-bolts having leg portions received by openings insaid branches on either side of said troughs.

5. The propping frame as defined in claim 1, wherein each channel andeach arm disposed therein are of conforming cross-section.

References Cited UNITED STATES PATENTS 3,283,514 11/1966 Launay 6l-45FOREIGN PATENTS 802,413 6/1936 France. 694,540 8/ 1940 Germany. 936,26212/ 1955 Germany. 976,923 12/ 1964 Great Britain.

JACOB SHAPIRO, Primaly Examiner.

